School of Community Science and Technology, Indian Institute of Engineering Science and Technology, Shibpur, India.
Food Funct. 2021 Jun 21;12(12):5501-5523. doi: 10.1039/d0fo03120h.
There is increasing attention on the exploration of waste feedstocks as economically viable substrates for the production of prebiotic oligosaccharides, especially xylooligosaccharides, as excellent candidates for the maintenance and promotion of gut microbiota. XOS, an emerging prebiotic that has several functional attributes and beneficial health effects, is mainly produced by different processes, especially enzymatic hydrolysis through the valorisation of xylan enriched lignocellulosic materials. The present study deals with the enzymatic production of xylooligosaccharide (XOS) from xylan rich cauliflower stalk, a novel source. Delignification with alkali (NaOH) was found to be more efficient than acid and autohydrolysis, resulting in a higher extraction yield of xylan (18.42%). Alkaline extraction for 120 minutes at 1.25 M alkali concentration produced maximum xylan yield. FTIR analysis of xylan extracted from cauliflower stalk by an alkaline (NaOH) pretreatment method showed typical absorption bands at 1729 cm-1 that correspond to acetyl groups exhibiting the typical xylan specific band. Enzymatic hydrolysis was carried out with indigenously produced crude endoxylanase obtained from Aspergillus niger MTCC 9687 and the effects of substrate concentration, enzyme concentration, pH, time and temperature were investigated. High resolution MS analysis showed the presence of xylobiose as the major XOS. The major 1H spectral signals of XOS liberated from enzymatically hydrolysed alkali extracted cauliflower stalk xylan showed the presence of β-anomeric protons in the spectral region of 4.0-4.7 ppm. Prebiotic efficacy of cauliflower stalk derived XOS alone and synbiotic combinations with known probiotic strains (Lactiplantibacillus plantarum, Bifidobacterium bifidum, Lactobacillus delbrueckii ssp. Helveticus) were evaluated. Butyrate was found to be the major short chain fatty acid produced by XOS supplemented fermentation media. All the synbiotic combinations showed significantly higher antioxidant and antimicrobial activities and reduced the viability of human bone cancer MG-63 cells. The individual profiles of antimicrobial components of XOS were identified as dihydroxy benzoic acid and aspartic acid by HPLC coupled to a photodiode array detector.
人们越来越关注探索废物饲料作为生产益生元低聚木糖（尤其是木二糖）的经济可行基质，因为它们是维持和促进肠道微生物群的优秀候选物。XOS 是一种新兴的益生元，具有多种功能特性和有益的健康影响，主要通过不同的工艺生产，特别是通过利用富含木聚糖的木质纤维素材料进行酶解来生产。本研究涉及从新型来源花椰菜茎富含木聚糖的材料中酶法生产木二糖（XOS）。与酸和自水解相比，用碱（NaOH）进行脱木质素发现更有效，导致木聚糖提取率更高（18.42%）。在 1.25 M 碱浓度下用碱（NaOH）提取 120 分钟可获得最大木聚糖产量。用碱性（NaOH）预处理方法从花椰菜茎中提取的木聚糖的 FTIR 分析显示出在 1729 cm-1 处对应于乙酰基的典型吸收带，乙酰基表现出典型的木聚糖特征带。用本土生产的黑曲霉 MTCC 9687 产粗内切木聚糖酶进行酶水解，研究了底物浓度、酶浓度、pH 值、时间和温度的影响。高分辨 MS 分析表明存在木二糖作为主要的 XOS。从酶解碱提取的花椰菜茎木聚糖中释放的 XOS 的主要 1H 光谱信号显示出在 4.0-4.7 ppm 光谱区域存在β-端基质子。单独评估了花椰菜茎衍生的 XOS 的益生元功效以及与已知益生菌株（植物乳杆菌、双歧杆菌、德氏乳杆菌亚种）的共生组合。发现丁酸是 XOS 补充发酵培养基中产生的主要短链脂肪酸。所有共生组合均表现出显著更高的抗氧化和抗菌活性，并降低了人骨肉瘤 MG-63 细胞的活力。XOS 的个别抗菌成分谱通过 HPLC 与光电二极管阵列检测器耦合鉴定为二羟基苯甲酸和天冬氨酸。
